1. Field of the Invention
The present invention relates generally to display interface systems.
2. Description of the Related Art
Display interface systems typically capture various types of analog video signals (e.g., RGB or YPbPr signals) and digitize them for presentation on advanced digital displays (e.g., computer displays and television displays). These interfaces generally include three converter channels that correspond to three video colors in addition to circuits directed to pixel clock generation, sampling phase control and output data formatting.
Various signal conditioning errors in a display interface can substantially degrade the quality of the resultant display. For example, a portion of analog input signals will be lost unless the dc level of these signals is successfully clamped to levels compatible with the processing circuits of each converter channel. For a second example, output code offset errors in the three converter channels will generate undesirable brightness variations in display colors. For a third example, channel gain errors will generate contrast variations in display colors.
Although some display interfaces have included clamping and offset control circuits which are intended to automatically restore and balance signal reference levels to thereby reduce offset differences, they have typically failed to provide controls that effectively include and integrate control of all display interface signal conditioning processes.